<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        let i = prompt("当前年")
        if(i%4==0||i%100!=0){
            alert("闰年")
        }else{
            alert("平年")
        }
    </script>
</body>
</html>